System

Typedefs
typedef uint32_t	clock_time_t
	Define a type to hold a system clock time.

Functions
void	clock_init (void)
	Use timer A0 to set up a system clock ticking at 1ms intervals.
void	sys_clock_init (void)
	Configure the system core clock to provide a stable clock for the CPU. More...
clock_time_t	clock_time (void)
	Return the current system time. More...
void	_delay_ms (clock_time_t delay)
	Delay for the provided number of milliseconds. More...
	interrupt (TIMER0_A0_VECTOR)
	Interrupt service routine for the system ticks counter. More...

Variables
static volatile clock_time_t	ticks
	Current clock time.

Detailed Description

Function Documentation

void _delay_ms

(

clock_time_t

delay

)

Delay for the provided number of milliseconds.

We use the __delay_cycles() function which consists of putting NOPs into the CPU pipeline for the required period.

Parameters

delay

The number of ms to delay.

clock_time_t clock_time

(

void

)

Return the current system time.

Returns

The current clock time in milliseconds.

interrupt

(

TIMER0_A0_VECTOR

)

Interrupt service routine for the system ticks counter.

Note that the interrupt() macro is from legacymsp430.h.

void sys_clock_init

(

void

)

Configure the system core clock to provide a stable clock for the CPU.

Set up the system core clock source as the digitally controlled oscillator (DCO) and have the FLL stabilise the DCO at 25MHz with reference to the external high speed crystal XT2, which is 4MHz on the MSP-EXP430 board.